<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // 检测昵称是否是有汉字字母数字下划线组成，6-8位
        while (true) {
            const a = prompt("请输入昵称")
            const reg = /^[\u4e00-\u9fa5\w]{6,8}$/
            if (reg.test(a)) {
                alert("true")
            } else {
                alert("false")
            }
        }

    </script>

</body>

</html>